Uryū Line began construction in 1922, to connect Shumarinai and Fukagawa. The construction was split in six phases and the construction was completed by 1932. The line was renamed to Horokanai Line in 1931. Meiu Line (名雨線) began construction in 1935 to connect Nayoro to Shumarinai. The line was completed in 1939, and the two lines were renamed to Shinmei Line, taking letters from the two terminus.
Post war In 1960s, due to the decline of coal mines and introduction of cheaper foreign woods, the economy of the nearby municipalities began to decline. This led to the slow decrease in the population. Population in Horokonai decreased to 7,283 by 1970 compared to 12,016 in 1960. In areas close to Shirakaba station and Fukinodai, settlements disappeared, and with the ongoing
motorization and the improvements in roads, the number of users fell to one-third of its peak. Following the huge drop in users and
operating ratio hitting 2,785, the line was listed as one of the
Deficit 83 Lines movement and later
Specified local lines. However, due to lack of replacement roads, it was not closed by the movement, the line continued to operate until 1995, when it was closed and switched to bus service by
JR Hokkaido Bus Company. ==Rolling stock==